Einsteins to Change Lightbulb

Q: How many Einsteins does it take to change a lightbulb?
A: That depends on the speed of the changer, and the mass of the bulb. Or vice versa, of course. Then it just might be easier to leave the bulb alone and change the room. It's all relative.

NASA Techs to Change Lightbulb

Q: How many NASA technicians does it take to change a lightbulb?
A: Seventy, and they plan it for two weeks and when they finally get around to it the weather's bad so they postpone it till next week. The lightbulb costs three million dollars.

Light Bulb - USENETers

Q: How many USENETers does it take to screw in a light bulb?
A: None. They are so busy hogging up bandwidth taking out their postadolescent frustrations on each other, that they never get around to it!